Low temperature scanning electron microscopy study of YBa2Cu3O7-delta multilayer dc SQUID magnetometers

Low temperature scanning electron microscopy (LTSEM) has been used to analyze the superconducting properties of integrated magnetometers involving a de superconducting quantum interference device. The study yielded spatially resolved information on the critical temperature T-c and critical current density J(c) in the upper and lower superconducting layers of the YBa2Cu3O7-delta/SrTiO3/YBa2Cu3O7-delta stricture. The T-c of the lower film was depressed by several kelvin, and the J(c) of the upper film was lower where it crossed the edge of a lower YBa2Cu3O7-delta film covered with SrTiO3. A gradient in T-c was observed in the lower film near the edge of a via, arising presumably from oxygen diffusion during fabrication. (C) 1996 American Institute of Physics.